Phosphorus is irreplaceable in living
systems. No other element can serve as a
substitute. The only way to ensure our supply
doesn’t run out is to figure out how to recycle
it, or curb usage. But for other endangered
elements, there are solutions beyond just
Depending on what it’s being used for, different elements can replace helium. Helium
can be swapped with hydrogen in balloons,
but hydrogen—which isn’t on the endangered
list—isn’t exactly an ideal addition to a birthday party, because it’s highly flammable. This
means candles, or any other fire, must be kept
far away. In some MRI machines, liquid nitrogen can do the job of liquid helium. Argon can
take the place of helium in welding. Increasing
the price of helium may also encourage more
efficient use overall.
Like helium, there are alternatives to the
indium tin oxide used in smartphones and
other touchscreen devices. Researchers are
figuring out how to make the same technology with more abundant alternatives, such as
carbon. Others are trying to make indium tin
oxide with less indium. However, there are still
challenges associated with each alternative.
In addition to looking for alternatives,
another solution is longer-lasting products.
Making more durable, longer-lasting products
may allow endangered element reserves to
last longer. If your phone, for example, can
survive screen-cracking falls or a swim in the
toilet, you won’t have to buy another, keeping
just that little bit of indium in reserves instead
of in your pocket.
Endangered Elements. American Chemical Society:
http://www.acs.org/content/acs/en/greenchem-istry/research-innovation/research-topics/endan-gered-elements.html [accessed Nov 2016].
Davies, E.; Renner, R. Endangered Elements:
Critical Thinking. Chemistry World, Jan 2011:
196054.pdf [accessed Nov 2016].
Cynthia D. Helium Shortage? It’s Not Just a
Bunch of Hot Air, Retailers Say. Chicago Tribune,
May 26, 2012: http://articles.chicagotribune.
algeria [accessed Nov 2016].
Chris Patrick is a science writer located in Richmond,
Va. This is her first article in ChemMatters.
regenerated, but the time frame is beyond
anything that makes sense to us humans,”
says David Atwood, a chemistry professor
at the University of Kentucky, Lexington, Ky.
“Right now, we are using up concentrated
helium that took millions of years to make.”
We cannot wait millions of years for more
radioactive elements to decay and replenish
the usable supplies of helium, which, in addi-
tion to birthday balloons, is used in welding
and medical imaging. When welders use elec-
tricity to melt and fuse two pieces of metal,
they also use a “shielding gas,” an inert (or
inactive) gas—like helium—that shields the
vulnerable, molten metal from contamination
by oxygen and water vapor in the atmo-
sphere. At hospitals, magnetic resonance
Indium, helium—these two
elements are important, but
without phosphorus, you
would not exist. No living
beings would. Phosphorus is
an ingredient of DNA, the
genetic blueprints inside every one of your
cells. It is also an important component of
your teeth and bones, and plants need it to
The most important product containing
phosphorus is the fertilizer used to grow
crops. Plants’ roots take up phosphorus from
water in soil. But phosphorus compounds are not very soluble in
water, so most soils have less
phosphorus available than plants
need. That is why modern agriculture relies
on phosphorus-containing fertilizers.
As the world population grows and needs
more food, the demand for phosphorus is also
rising. We mine phosphorus from rock, but
scientists estimate that in 30 to 40 years there
will not be enough phosphorus left in reserves
to meet agricultural demand. Not enough
phosphorus means not enough fertilizer,
which means not enough food.
That is why phosphorus is shaded yellow
on the Periodic Table of Endangered elements.
imaging (MRI) machines take pictures of the
inside of organs, tissues, and tumors using
magnetic fields. They need liquid helium to
cool the special magnets that make these
fields in the machine.
We might be able to extend the lifetime of
this helium reserve if we set up a way to recycle the element. But because helium is cheap,
recycling it is not yet cost effective.
Its reserves are not quite as depleted as those
of indium and helium, but it is in limited
supply. Although there is a limited supply of
phosphorus in reserves, there is still the same
amount of phosphorus on Earth. Just like
indium, the phosphorus that was once found
in rocks is now more spread around. We cannot keep mining for it in the same spots, but
we may be able to recycle the phosphorus that
we have already used.
Excess phosphorus from crop
fertilizers that was not taken up
by plant crops ends up in the runoff that flows out of crop fields
and into nearby bodies of water.
We, and other animals, also excrete phosphorus in our waste, which also eventually finds
its way to water. Some people wonder if we
might be able to extract phosphorus from
water and waste to re-use it in agriculture.
Will we figure out how to recycle phosphorus
before demand exceeds supply?
Helium, continued from p. 17
Phosphorus feeds our food